Stress and microstructure evolution in thick sputtered films

Structural and mechanical analysis for the optimization of PVD oxide coatings for protection against metal dusting

“…There are numerous studies that consider the influence of bias voltage on the development of residual stresses [10,16,21,23]. These studies agree that the extra energy supplied by the application of the bias voltage to the species reaching the substrate provides them with enough mobility, not only to fill the gaps between columns and thus reduce the tensile stresses [23], but also to produce an "ionpeening" effect.…”

“…In this case, when contiguous columns are close enough, interatomic attractive forces act between the column walls which stretch the columns and thus tensile stresses develop inside them if the film is well adhered. This is the so-called grain boundary relaxation mechanism to explain the origin of tensile growth stresses [10,16,[21][22][23]. Furthermore, the low deposition temperature and relatively high deposition pressure of the present experiments were conditions that led to low energy, and thus low mobility, of the species arriving at the surface of the substrate.…”

“…In general, Physical Vapor Deposition (PVD) processes for the deposition of wear resistant films result in compressive stresses on the order of a few GPa [13][14][15]. However, sputtering processes may also result in tensile stresses, especially when the sputtering gas pressure is high or the substrate bias is low [16].…”

Thick Beryllium Coatings by Magnetron Sputtering

“…To enhance the plasma density near substrates and supply extra flux of energized ion to the growing films, a secondary plasma was introduced near the substrate region and a negative biasing was added to the substrate to extract ions. The details of this ion-assisted physical vapor deposition (IPVD) process have been described elsewhere [11].…”

“…Residual stress measurements were carried out insitu on flat Si substrates using a multi-beam optical sensor (MOSS) system manufactured by kSpace Associates, Inc. This system uses an array of parallel laser beams reflecting from the growing substrate surface to measure surface curvature and then convert the measured curvature to stress by using the Stoney formula [11]. The Si substrate has a thickness of 500 μm to ensure accurate measurements.…”